Method for manufacturing a thermoacoustic insulation module for an aircraft comprising a bending step

ABSTRACT

In order to facilitate the thermoacoustic insulation of an aircraft portion, a method for manufacturing a thermoacoustic insulation module for an aircraft comprises a step of providing a mat configured to provide thermoacoustic insulation of an aircraft portion, followed by a step of attaching a bendable structure to the mat, followed by a step of bending the bendable structure, along a bending axis parallel to a longitudinal direction of the mat, such that the bendable structure forms a load-bearing structure supporting the mat in a curved shape.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of the French patent application No.1663217 filed on Dec. 22, 2016, the entire disclosures of which areincorporated herein by way of reference.

TECHNICAL FIELD

The present invention relates to the field of thermal and acousticinsulation systems for aircraft and has the general aim of improving theincorporation of these systems into aircraft, in particular intoaircraft cabins.

More particularly, the invention concerns a method for manufacturing athermoacoustic insulation module intended for the thermal and acousticinsulation of an aircraft.

BACKGROUND OF THE INVENTION

In an aircraft, the purpose of the thermal and acoustic insulationsystem, also referred to as “thermoacoustic insulation,” is to insulatethe aircraft from the noises, in particular the aerodynamic noises, andthe cold encountered during flight at normal cruising altitudes.Generally, the insulation relates to the aircraft cabin, which isintended to accommodate the crew and passengers, whereas the holdgenerally is not insulated.

In known types of aircraft, the thermoacoustic insulation system forinsulating the cabin comprises a plurality of padded panels, eachassembled on the structure of the aircraft. A typical medium-haulaircraft therefore contains approximately three hundred padded panels.The geometry of these panels varies depending on their respectivelocations inside the aircraft, and they are generally produced for themost part manually and incorporated manually into the structure of theaircraft.

Operations for installing the thermoacoustic insulation system in theaircraft are therefore long and costly, and furthermore take over theaircraft, in that it is not generally possible to carry out otheroperations on the aircraft while the thermoacoustic insulation system isbeing installed.

In view of the increasing rates of aircraft production, it is thereforedesirable to improve the methods used to incorporate thermoacousticinsulation systems into aircraft.

SUMMARY OF THE INVENTION

The idea underlying the invention comprises replacing a plurality ofpadded panels used to constitute a known type of thermoacousticinsulation system, with a single mat, the latter therefore havingdimensions considerably larger than the dimensions of the padded panelsused in the prior art.

This principle offers numerous advantages, including:

time saving when installing a thermoacoustic insulation system in anaircraft, such a saving being particularly advantageous because thisoperation is part of the critical path of aircraft assembly procedures;

significant weight saving (for example of the order of 15%), because theknown types of insulation system require an overlap between theirmultiple adjacent panels;

money saving, in particular due to the possibility of automating much ofthe manufacture of the thermoacoustic insulation module, and due to thereduced time required to thermoacoustically insulate an aircraft bymeans of such a module;

improved efficiency in terms of thermoacoustic insulation, owing to aconsiderable reduction in leaks and thermal bridges, in particular as aresult of the reduction in the number of edges.

In this context, the invention proposes a method for manufacturing athermoacoustic insulation module for an aircraft, comprising at least:

a step of providing a mat intended for the thermoacoustic insulation ofan aircraft portion; followed by

a step of attaching a bendable structure to the mat; followed by

a step of bending the bendable structure, along a bending axis parallelto a longitudinal direction of the mat, such that the bendable structureforms a load-bearing structure supporting the mat in a curved shape, theload-bearing structure and the mat together forming said thermoacousticinsulation module.

The manufacturing method according to the invention proposes to givesuch a mat a curved shape by using the bendable nature of a structurepreviously connected to the mat. The curved configuration of the mat inthe thermoacoustic insulation module then helps facilitate theinstallation of the mat on an aircraft structure similar in shape.

The method according to the invention therefore offers a simple,economical and effective means for manufacturing a thermoacousticinsulation module comprising such a mat, offering advantageous optionsin terms of installation in an aircraft.

In preferred embodiments of the invention, the step of providing the matcomprises at least:

a step of providing a raw mat; followed by

a step of producing the mat from the raw mat, comprising the productionof a plurality of porthole openings and/or at least one aircraft cabindoor opening in the raw mat.

Preferably, the step of providing the raw mat comprises a step ofproducing the raw mat comprising at least:

a step of depositing a first layer of thermoacoustic insulation on anouter film; followed by

a step of depositing a second layer of thermoacoustic insulation on oneor more first areas of the first layer of thermoacoustic insulation,leaving one or more second areas of the first layer of thermoacousticinsulation not covered by the second layer of thermoacoustic insulation;followed by

a step of depositing an inner film on the second layer of thermoacousticinsulation and on the second areas of the first layer of thermoacousticinsulation.

In preferred embodiments of the invention, the bendable structurecomprises bendable battens, the step of attaching the bendable structureto the mat comprising a step of attaching the bendable battens to themat such that the bendable battens are arranged in a transversedirection of the mat orthogonal to the longitudinal direction, andspaced apart from each other in the longitudinal direction.

Preferably, the step of attaching the bendable structure to the matcomprises a step of attaching reversible attachment devices to the mat,followed by the step of attaching the bendable battens to the mat, bymeans of the reversible attachment devices.

Preferably, the method further comprises a step of attaching feetrespectively to two opposing ends of each of the bendable battens, thefeet being provided with wheels and/or lifting actuators.

Preferably, the method comprises, between the step of attaching thebendable battens to the mat and the step of bending the bendablestructure, a step of compacting the mat that comprises at least:

raising the segments of the mat each situated between two correspondingconsecutive bendable battens, in such a way as to give the mat anundulated shape in the longitudinal direction; and

bringing the segments closer together, and moving the bendable battenscloser together, by compressing the segments, in such a way as to reducethe space requirement of the mat in the longitudinal direction.

Preferably, the method further comprises a step of connecting thebendable battens to at least one synchronization device, connecting thebendable battens to each other in such a way as to synchronize themovements of the bendable battens relative to each other in thelongitudinal direction.

Preferably, the method further comprises a step of installing alongitudinal retaining device configured to prevent the bendable battensfrom moving apart from each other in the longitudinal direction.

In preferred embodiments of the invention, the method further comprisesa step of installing a transverse retaining device configured to holdthe load-bearing structure in its bent shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clearly understood, and other details,advantages and features of the invention will become apparent, uponreading the description below provided as a non-limiting example, withreference to the appended drawings in which:

FIG. 1 is a schematic perspective view of a machine for automaticallyimplementing steps of manufacturing a mat, in the context of a methodaccording to a preferred embodiment of the invention;

FIGS. 2 and 3 are partial schematic perspective views of a raw matduring a step of producing said raw mat;

FIG. 4 is an exploded cross-sectional view of the raw mat of FIGS. 2 and3;

FIGS. 5 to 7 are partial schematic perspective views of a mat during astep of producing said mat from the raw mat of FIGS. 2 to 4;

FIG. 8 is a partial schematic perspective view of the mat, showing astep of attaching bendable battens forming a bendable structure on themat;

FIGS. 9 and 10 are schematic perspective views of at least a portion ofthe mat and the bendable battens, showing a step of compacting the mat;

FIG. 11 is a partial schematic perspective view of the mat and thebendable battens, showing a step of connecting the bendable battens to adeployment device;

FIGS. 12 to 14 are schematic perspective views of the mat and thebendable structure, showing a step of bending the bendable structure toform a load-bearing structure, said load-bearing structure forming, withthe mat, a thermoacoustic insulation module;

FIG. 15 is a partial schematic perspective view of the mat and of thebendable structure equipped with a longitudinal retaining device and atransverse retaining device;

FIG. 16 is a schematic view in longitudinal cross section of a bendableelement, in the non-bent state;

FIG. 17 is a schematic view in longitudinal cross section of thebendable element of FIG. 16, in the bent state;

FIG. 18 is a larger-scale view of a part A of FIG. 17;

FIG. 19 is a partial schematic perspective view of the bendable elementof FIG. 16;

FIG. 20 is a partial schematic view in longitudinal cross section of abendable batten, in the non-bent state;

FIG. 21 is a schematic view in longitudinal cross section of thebendable batten of FIG. 20, in the bent state;

FIG. 22 is a larger-scale view of a part B of FIG. 21;

FIG. 23 is a schematic perspective view of the bendable structure,formed from bendable battens similar to the bendable batten of FIG. 20,during the step of bending this structure shown in FIGS. 12 to 14;

FIG. 24 is a partial schematic perspective view of an aircraft structureand the thermoacoustic insulation module of FIG. 14, during a step ofinserting this module into a space delimited by the aircraft structure;

FIG. 25 is a partial schematic perspective view of the thermoacousticinsulation module alone, showing a step of actuating a deployment devicethat brings the load-bearing structure into a deployed configuration andthe mat into an installation configuration;

FIG. 26 is a partial schematic perspective view of the aircraftstructure and the thermoacoustic insulation module after the step ofactuating the deployment device, shown in FIG. 25;

FIG. 27 is a similar view to FIG. 26, showing the thermoacousticinsulation module alone;

FIG. 28 is a side schematic view of the thermoacoustic insulationmodule, showing a step of attaching opposing longitudinal ends of theload-bearing structure to the aircraft structure;

FIG. 29 is a schematic view, in cross section according to the plane Sof FIG. 26, of the aircraft structure and the thermoacoustic insulationmodule;

FIG. 30 is a similar view to FIG. 25, showing a step of raising theload-bearing structure of the thermoacoustic insulation module;

FIG. 31 is a similar view to FIG. 29, showing the step of raising theload-bearing structure of the thermoacoustic insulation module;

FIGS. 32 to 34 are partial schematic views, in cross section accordingto the plane S of FIG. 26, of the aircraft structure and thethermoacoustic insulation module, showing a step of detaching the matfrom the load-bearing structure and a step of attaching the mat to theaircraft structure;

FIG. 35 is a schematic cross-sectional view of an elastic clip attachingthe mat to the aircraft structure;

FIG. 36 is a similar view to FIG. 29, showing the aircraft structureequipped with the mat, after removing the load-bearing structure.

In all of these figures, identical reference numbers can denoteidentical or similar elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As explained above, the idea underlying the invention comprisesreplacing a plurality of padded panels used to constitute a known typeof thermoacoustic insulation system with a single mat, the lattertherefore having dimensions considerably larger than the dimensions ofthe padded panels used in the prior art.

FIGS. 1 to 15 show a method for manufacturing a thermoacousticinsulation module for an aircraft according to a preferred embodiment ofthe invention, comprising such a mat. The method described as anillustrative example concerns the insulation of an airplane cabin, i.e.,the substantially semi-cylindrical space situated above a floor of theairplane, but can be applied similarly to the insulation of other partsof an airplane or any type of aircraft.

FIGS. 16 to 23 show an example of a bendable structure and of a bendingmethod, used in the method for manufacturing a thermoacoustic insulationmodule according to the preferred embodiment of the invention.

FIGS. 24 to 36 show a thermoacoustic insulation method for insulating aportion of an aircraft by means of the thermoacoustic insulation module,and make it possible to appreciate the advantages obtained by such amodule.

In the present description as a whole, the longitudinal direction X ofthe mat is defined as being the direction parallel to the longitudinaldirection of the aircraft equipped with such a mat, i.e., the directionof the roll axis of the aircraft. The transverse direction Y is definedas being the direction orthogonal to the longitudinal direction X and tothe vertical direction Z of the aircraft. When the mat is arranged flat,the transverse direction Y of the mat corresponds to the directioncontained in the plane of the mat and orthogonal to the longitudinaldirection X, while the vertical direction Z corresponds to the thicknessdirection of the mat.

FIG. 1 shows, schematically, a machine 10 suitable for automaticallyimplementing steps of the manufacturing method.

To this end, the machine 10 comprises a support plate 12 of largedimensions, for example larger than the dimensions of a semi-cylindricalportion of an airplane fuselage rolled out flat, enabling such a mat tobe supported.

The machine 10 further comprises gantries 14 equipped with numericallycontrolled tools 16 dedicated, for example, to operations for deployingreels of film and reels of insulating material, cutting operations,welding operations, stitching operations, marking operations, and mathandling operations.

It is clear to a person skilled in the art that the configuration of themachine 10 can easily be adapted to the configuration of thethermoacoustic insulation module that is to be manufactured, whichdepends on the configuration of the aircraft that is to be equipped.

The mat is produced from a raw mat, which is itself manufactured by thesuperposition of layers of insulating material and wrapping film.

These layers can be formed by assembling, for example by heat welding,layers of material 20 with a width smaller than that of the mat that isto be manufactured, connected along longitudinal lines 22 (FIG. 2).

As a variant, at least some of the layers of material forming the rawmat can be formed directly from reels having the full width of the matthat is to be manufactured, as explained below.

FIG. 3 shows a step of producing the raw mat, and shows, from right toleft:

an outer film 30 intended to form an outer surface 31 of the raw mat,

the result of a step of depositing a first layer of thermoacousticinsulation 32 on the outer film 30,

the result of a subsequent step of depositing a second layer ofthermoacoustic insulation 34 on first areas 36A of the first layer ofthermoacoustic insulation 32, leaving one or more second areas 36B ofthe first layer of thermoacoustic insulation 32 not covered by thesecond layer of thermoacoustic insulation 34, and

the raw mat 40, an exploded cross-sectional view of which can also beseen in FIG. 4, obtained after a subsequent step of depositing an innerfilm 38 on the second layer of thermoacoustic insulation 34 and on thesecond areas 36B of the first layer of thermoacoustic insulation 32. Theinner film 38 is intended to form an inner surface 39 of the raw mat.

Each of the layers 30, 32, 38 is obtained from a correspondingfull-width reel 30A, 32A, 38A (FIG. 3), whereas the second layer ofthermoacoustic insulation 34 is deposited in the form of narrowerstrips, formed from a reel 34A of corresponding width.

Depositing the second layer of thermoacoustic insulation 34 on the firstareas 36A of the first layer of thermoacoustic insulation 32 helps givesaid areas enhanced insulation properties compared to the second areas36B. The method therefore makes it possible to satisfy the need forareas of locally enhanced insulation, which is common in aircraft, andwhich is satisfied in the prior art by using padded panels that havedifferent levels of insulation.

The method then comprises a step of producing the mat 50 of thethermoacoustic insulation module from the raw mat 40, by implementingfinishing operations that are applied to the raw mat.

These finishing operations comprise, for example, the creation of tworows of porthole openings 52A, 52B (FIG. 5) arranged on two opposinglateral sides of the mat, and several aircraft cabin door openings 54,in the raw mat.

The finishing operations generally comprise operations for cutting outthe outer contours and inner contours of the mat, and operations forwelding the outer film 30 to the inner film 38 to seal the mat closed atthe outer and inner contours. These operations also preferably compriseoperations for producing padding studs housed between the inner andouter films to prevent deformations of the layers of insulation 32, 34.

The finishing operations can further comprise the creation of markingson the inner surface 39 (FIG. 6), which advantageously includetransverse markings 60 that coincide with the intended location ofcontact between the mat and the circumferential frames of the airplanefuselage, as will become more clearly apparent below. Other markings 62can be used to locate precutting areas, with a view to facilitatingpossible subsequent repairs of the mat, or to mark locations intended tobe perforated in order to allow supports of various systems of theairplane to pass through same. With respect to possible subsequentrepairs of the mat, a damaged area can indeed be removed by followingthe precutting markings, ensuring that the dimensions of the removedpart are known in advance. This means that having a range of repair kitswith the dimensions of the areas delimited by the precutting markings issufficient in order to ensure the maintenance of the mat as a whole.

Once the mat 50 has been produced, the method generally proceeds with astep of attaching a bendable structure to the mat.

This step comprises first attaching reversible attachment devices 70 tothe mat (FIG. 7). These devices 70 each form, for example, the loop partor the hook part of a hook and loop device. These devices 70 areadvantageously positioned along the abovementioned markings 60.

Next, bendable battens 80, together forming the abovementioned bendablestructure 82, are attached to the mat (FIG. 8) by means of thereversible attachment devices 70. Naturally, to this end, the battenscomprise the other parts (with hooks or loops) which make it possible toform, in cooperation with the devices 70, hook and loop devices.

The bendable battens 80 are therefore detachably attached to the mat,and are thus arranged along the abovementioned markings 60, parallel tothe transverse direction Y of the mat, and spaced apart from each otherin the longitudinal direction X. The bendable battens incorporate feet84 (partially visible in FIG. 8) at their ends. As a variant, the lattercan be mounted on the bendable battens 80 at a later stage. The feet 84are provided with respective wheels and lifting cylinders (not shown inFIG. 8).

The method then comprises a step of compacting the mat 50. This stepcomprises firstly raising the segments 90 of the mat each situatedbetween two corresponding consecutive bendable battens 80, in such a wayas to give the mat an undulated shape in the longitudinal direction X(FIG. 9), and secondly of bringing the segments 90 closer together, andmoving the bendable battens 80 closer together, by compressing thesegments 90, in such a way as to reduce the space requirement of the matin the longitudinal direction X (FIG. 10). Using this method, the spacerequirement of the mat can typically be reduced by a factor of 10.

As with the preceding operations, the compacting operations areadvantageously well suited to automated implementation.

The method then comprises a step of connecting the bendable battens 80to at least one synchronization device 110 (FIG. 11), connecting thebendable battens 80 to each other in such a way as to synchronize themovements of the bendable battens relative to each other in thelongitudinal direction X, as will become more clearly apparent below.

In the example shown, there are two synchronization devices 110, eachcomprising a plurality of deformable parallelograms 112 articulated witheach other in series and respectively connected to the bendable battens80.

Each synchronization device 110 therefore comprises two sets 114A, 114Bof rods mounted end to end, being articulated with each other by theirrespective ends, the rods of the first set 114A being furtherarticulated with the rods of the second set 114B by their respectivemiddles, in such a way as to form said plurality of deformableparallelograms 112, as will become more clearly apparent below.

As shown in FIG. 11, the synchronization devices 110 are advantageouslyarranged respectively in two longitudinal recesses 116A, 116B formed inthe top surface 118 of the compacted mat, respectively by the two rowsof porthole openings 52A, 52B.

The step of connecting the bendable battens 80 to the synchronizationdevices 110 can, as a variant, be implemented before the step ofcompacting the mat 50.

As shown in FIG. 12, the method next preferably comprises a step ofturning over the mat 50 provided with the bendable battens 80 and thesynchronization devices 110 (the latter not being visible in FIG. 12).

The method next comprises a step of bending the bendable structure 82,along a bending axis 130 parallel to the longitudinal direction X of themat 50 (FIGS. 13 and 14). In this case, this step comprises bending thebendable battens 80, which then constitute bent battens.

In its bent configuration, the bendable structure thus forms aload-bearing structure 140 supporting the mat 50 in a curved shape, withan axis of curvature corresponding to the bending axis 130.

In order to ensure the stability of the assembly, the manufacturingmethod advantageously comprises a step of installing a longitudinalretaining device 150 configured to prevent the bent battens 80 frommoving apart from each other in the longitudinal direction X (FIG. 15),and a step of installing a transverse retaining device 152 configured tohold the load-bearing structure 140 in its bent shape. These devices,which are formed from bars and fastening members for fastening to theload-bearing structure 140, are shown very roughly and will not bedescribed in detail, since a person skilled in the art is capable ofdesigning such devices by means of conventional methods from theindications provided above.

As a variant, the bendable battens 80 can be attached non-detachably tothe mat, by non-reversible means, without departing from the scope ofthe invention.

As a further variant, the manufacturing method may not comprise a stepof compacting the mat, in which case the step of connecting the battensto the synchronization devices is also omitted.

The assembly constituted by the load-bearing structure 140 and the mat50, and the longitudinal retaining device 150 and transverse retainingdevice 152, thus forms the thermoacoustic insulation module 154 obtainedat the end of the manufacturing method described above.

In view of the explanations above, it is clear that the load-bearingstructure 140 is attached to the mat 50 in a detachable manner.

Moreover, it should be understood that the load-bearing structure 140 isdeployable from a retracted configuration in which it is retracted alongthe longitudinal direction X of the mat, corresponding to a compactedconfiguration of the mat 50, to a deployed configuration in which it isdeployed along the longitudinal direction X, corresponding to aninstallation configuration of the mat.

Such a deployment is implemented by deforming the deformableparallelograms 112 that constitute the synchronization devices 110.

The retracted configuration of the load-bearing structure 140 istherefore a configuration in which the bent battens 80 are relativelyclose together, and in which the deformable parallelograms 112 have anelongate shape in the vertical direction, whereas the deployedconfiguration of the load-bearing structure 140 is a configuration inwhich the bent battens 80 are relatively far apart from each other, andin which the deformable parallelograms 112 have an elongate shape in thelongitudinal direction.

As a variant, this load-bearing structure 140 can be designed so as tobe non-detachable, without departing from the scope of the presentinvention.

As a further variant, the load-bearing structure 140 may not be of adeployable native, without departing from the scope of the presentinvention.

Generally, supporting the mat 50 in its curved shape allows the mat tobe installed easily in an aircraft portion that is to be insulated, aswill become more clearly apparent below. This makes it possible to use amat of large dimensions to insulate the whole, or at least a major part,of a portion of an aircraft, such as a cabin.

The mat is therefore typically between 4 meters and 15 meters wide, andbetween a few meters (in the case of a mat intended to insulate a smallsection of cabin) and several tens of meters long, typically between 20meters and 100 meters long (in the case of a mat intended to insulatethe whole or nearly all of a cabin).

Moreover, the angle of curvature a of the mat (FIG. 14) is typicallygreater than 120 degrees, and is preferably equal to approximately 180degrees.

Moreover, as a result of its reduced space requirement in the retractedconfiguration, the thermoacoustic insulation module 154 according to thepreferred embodiment of the invention described above can easily bestored until it is used to insulate an aircraft portion.

A bendable structure and a bending method, used in the method formanufacturing the thermoacoustic insulation module according to thepreferred embodiment of the invention, will now be described inreference to FIGS. 16-23.

FIGS. 16 to 19 show a bendable element 160 that comprises an inflatableenvelope 161, capable of being inflated typically under a pressure of afew bars, and a first elongate, bendable base plate 162, attached to afirst face of the inflatable envelope, a second base plate 163, that isalso bendable and elongate, attached to a second face of the inflatableenvelope opposite the first face, and links 164 connecting the firstbase plate 162 to the second base plate 163. Moreover, the second baseplate 163 is shorter than the first base plate 162.

Naturally, the inflatable envelope 161 comprises a connector 165 forconnecting it to a pressurized gas source 166 in order to inflate theenvelope 161.

When the relative pressure inside the inflatable envelope 161 is zero,the geometry of the bendable element 160 is substantially planar (FIG.16). However, when the relative pressure inside the inflatable envelope161 is sufficiently high, the bendable element 160 adopts a bentgeometry, i.e., an arcuate geometry (FIGS. 17-19). More specifically,the action of inflating the inflatable envelope 161 causes the first andsecond base plates 162, 163 to bend in a direction of curvature Dextending from the first base plate 162 to the second base plate 163.

The arcuate shape induced by the action of inflating the inflatableenvelope 161 results from the fact that the second base plate 163 isshorter than the first base plate 162, and from the arrangement of thelinks 164 connecting the first base plate 162 to the second base plate163.

Indeed, these links 164 are arranged in such a way as to be slack whenthe inflatable envelope 161 is in a deflated state, and such that theaction of inflating the inflatable envelope results in the tensioning ofthe links 164, culminating with the links extending along radii ofcurvature 170 common to the first and second base plates 162, 163. Thelinks 164 then hold the second base plate 163 centered longitudinallyrelative to the first base plate 162. It should therefore be understoodthat the links 164, when tensioned, extend in respective directions thatconverge towards a common center C, thus corresponding to the center ofcurvature of the first and second base plates 162, 163.

As shown in FIG. 17, the first and second base plates 162, 163 are thencentered longitudinally relative to a same transverse plane P, and forma bending angle θ of the bendable element 160. The first base plate 162,which extends on a radially outer side of the bendable element 160, thusdefines a radius of curvature R1, while the second base plate 163, whichextends on a radially inner side of the bendable element, defines aradius of curvature R2. Moreover, the spacing T between the first andsecond base plates 162, 163, which is equal to the difference betweenthe radii of curvature R1 et R2, defines the thickness of the bendableelement.

In order to be able to be bent, the first and second base plates 162,163 are flexible but nevertheless have a certain degree of rigidity. Tothis end, the first and second base plates are advantageously producedfrom a composite material of the CFRP (a composite with acarbon-fiber-reinforced plastic matrix) or GFRP (a composite with aglass-fiber-reinforced plastic matrix) type. The first and second baseplates can thus be similar to the bending battens of certain boat sails.

The links 164 are preferably inextensible flexible threads, such asthreads produced from high-tenacity aramid fibers, for example frompoly-paraphenylene terephthalamide or PPD-T (a material known under theregistered trademark “Kevlar”).

Moreover, the junction points 172 of the links 164 with the first andsecond base plates 162, 163 are preferably distributed in a uniformmanner at the surface of each of these first and second base plates(FIGS. 17-19).

In the example shown in the figures, the base plates are housed in theinflatable envelope. This helps ensure the tight sealing of theinflatable envelope in a simple manner

As a variant, the base plates can be attached to an outer surface of theinflatable envelope. In this case, the links connect together parts ofthe inflatable envelope to which the first and second base platesrespectively are attached. The links therefore indirectly connect thebase plates to each other.

The bendable element 160 described above can be bent by means of abending method comprising the steps:

providing the bendable element 160, of which the inflatable envelope 161is in the deflated state and the first and second base plates 162, 163are not bent,

connecting the inflatable envelope 161 to a pressurized gas source 166(FIG. 16),

inflating the inflatable envelope 161 by means of the pressurized gassource 166, until the links 164 of the bendable element are tensioned insuch a way that the first and second base plates 162, 163 assume a bentshape.

The bendable element 160 described above can be used as it is as abendable batten in the context of the method for manufacturing thethermoacoustic insulation module described above.

However, for purely geometric reasons, the bending angle of the bendableelement 160 described above is limited to approximately 114 degrees.

Yet, it is preferable to have a bendable batten that has a bending anglegreater than the abovementioned limit

To this end, as shown in FIGS. 20-22, a bendable batten 80, used in themethod for manufacturing the thermoacoustic insulation module describedabove, is formed at least from one junction element 200, and from twobendable elements 160 of the kind described above, similar to eachother, the first respective base plates 162 of which have adjacentrespective ends 202 attached to the junction element 200.

As shown in FIG. 21, the bendable elements 160 of this bendable batten80 are advantageously shaped such that the first and second base plates162, 163 of each of the bendable elements form a bending angle θ ofbetween 57 degrees and 115 degrees.

Thus, the bendable batten has a bending angle Ω higher than 114 degrees,and capable of reaching 230 degrees.

The function of the junction element 200 is to make the junction betweenthe two bendable elements 160 more rigid. To this end, the connectionbetween each of the first respective base plates 162 of the two bendableelements 160 and the junction element 200 is an interlocking connection.

The junction element 200 preferably has a small extent in thelongitudinal direction of the bendable elements 160, such that thejunction area between each of the first base plates 162 and thisjunction element 200 is substantially planar, including when thebendable batten 80 is in the bent state. The junction element 200 cantherefore indiscriminately have a planar or curved attachment surfacefor receiving the first base plates 162.

The respective inflatable envelopes 161 of the two bendable elements 160can be provided with respective connectors in order to each be connectedto a pressurized gas supply source.

As a variant, in the example shown in FIGS. 20-22, the respectiveinflatable envelopes 161 of the two bendable elements 160 are broughtinto fluid communication with each other by a connection element 220(FIG. 22). In this case, only one of the respective inflatable envelopes161 of the two bendable elements 160 is provided with a connector 165,allowing both of the inflatable envelopes 161 to be connected to apressurized gas supply source.

The bendable batten 80 described above can be bent by means of a bendingmethod comprising the steps:

providing the bendable batten 80, in which the inflatable envelope 161of each bendable element 160 is in the deflated state and the first andsecond base plates 162, 163 of each bendable element 160 are not bent,

connecting the respective inflatable envelopes 161 of the bendableelements 160 of the bendable batten 80 to at least one pressurized gassource 166,

simultaneously inflating the respective inflatable envelopes 161 of thebendable elements 160 of the bendable batten 80 by means of thepressurized gas source 166, until the links 164 of each bendable element160 are tensioned in such a way that the first and second base plates162, 163 of each bendable element assume a bent shape.

In the preferred embodiment of the invention, the inflatable envelopes161 are connected to a same pressurized gas source 166 by means of theconnector 165 of one of the inflatable envelopes 161.

Naturally, bendable elements 160 of the kind described above can be usedsimilarly for forming a bendable batten comprising three bendableelements 160 arranged end to end or more, in order to give the batten abending angle of more than 230 degrees.

The bendable battens 80 of the kind described above are used to form thebendable structure 82, shown in FIG. 23 in its bent shape correspondingto the load-bearing structure 140. In this structure, the bendablebattens 80 are centered relative to a same plane V transverse to thefirst and second base plates 162, 163 of the bendable elements 160forming the bendable battens 80.

Preferably, the connectors of each bendable element, or the respectiveconnectors 165 of a bendable element 160 of each bendable batten 80, areconnected to a same pressurized gas source 166 by a pressurized gasdistribution circuit 230.

In view of the preceding description of the bendable structure 82, it isclear that the step of bending this structure can comprise a methodcomprising the steps:

providing the bendable structure 82, in which the inflatable envelope161 of each bendable element 160 is in the deflated state and the firstand second base plates 162, 163 of each bendable element 160 are notbent,

connecting the respective inflatable envelopes 161 of the bendableelements 160 of the bendable structure 82 to at least one pressurizedgas source 166,

simultaneously inflating the respective inflatable envelopes 161 of therespective bendable elements 160 of the bendable structure 82 by meansof the pressurized gas source 166, until the links 164 of each bendableelement 160 are tensioned in such a way that the first and second baseplates of each bendable element assume a bent shape.

A thermoacoustic insulation method for insulating a portion of anaircraft by means of the thermoacoustic insulation module 154 will nowbe described in reference to FIGS. 24 to 36.

FIG. 24 shows an aircraft structure 240, more particularlycircumferential frames of an airplane fuselage 242, and floor beams 244.The frames 242 and the beams 244 delimit, above the beams, an aircraftportion 245 that is intended to constitute a cabin of the aircraft and,below the beams, a portion intended to constitute a hold of theaircraft, in a manner that is well known. In the example described here,the insulation method concerns the portion intended to constitute thecabin.

In order to facilitate the insertion of the thermoacoustic insulationmodule 154 into the aircraft portion 245 that is to be insulated, tworails 246A, 246B are arranged in the longitudinal direction X of theaircraft, on the ends of the floor beams 244.

The thermoacoustic insulation module 154 is mounted on the rails 246A,246B by engaging the wheels 250 of the feet 84 of the bendable battens80 in the rails, as shown more clearly in FIG. 25, which shows asubsequent step of the method.

Next, the thermoacoustic insulation module 154 is moved along the railsuntil it enters the aircraft portion 245, as symbolized by the arrow 248in FIG. 24.

Given that the load-bearing structure 140 of the thermoacousticinsulation module 154 is in its retracted configuration, the insulationmethod then comprises a step of deploying the load-bearing structure 140in such a way as to bring the mat 50 into its installationconfiguration.

The deployment step comprises moving the longitudinal ends of theload-bearing structure 140 apart from each other, in such a way as tomove the bent battens 80 apart from each other by deforming thedeformable parallelograms 112 that constitute the synchronizationdevices 110, as explained above and as shown in FIG. 25.

At the end of this deployment step, the bent battens 80 are preferablypositioned respectively facing the circumferential fuselage frames 242.

FIG. 26 shows the aircraft structure 240 containing the thermoacousticinsulation module 154, the load-bearing structure of which is in thedeployed configuration. The thermoacoustic insulation module 154 in thisconfiguration is also shown on its own in FIG. 27 for greater clarity.

The method then comprises a step of attaching opposing longitudinal ends280, 282 of the load-bearing structure 140 to the aircraft structure 240delimiting the aircraft portion that is to be insulated, in such a wayas to apply tensile stress F to the load-bearing structure 140 in thelongitudinal direction X (FIG. 28).

FIG. 29 is a cross sectional view according to the plane S of FIG. 26,and thus shows a circumferential fuselage frame 242, a floor beam 244,and a bent batten 80 resting on its two feet 84, on which batten the mat50 rests in its curved shape. FIG. 29 in particular shows the wheels 250engaged in the abovementioned rails 246A, 246B, and the two liftingcylinders 290 respectively integrated with the feet 84.

The method next comprises a step of lifting the load-bearing structure140 (arrow 300) by means of the lifting cylinders 290 (FIG. 30), in sucha way as to move a top part 310 of the mat 50 closer to a top part 312of the aircraft structure 240 (FIG. 31). The top part 310 is the partresting on the bent battens 80.

The method next comprises a step of detaching the mat 50 from theload-bearing structure 140 and a step of attaching the mat 50 to theaircraft structure 240.

The mat is detached, as shown in FIG. 32, by releasing the attachmentprovided by the reversible attachment devices 70. In this case, thisinvolves separating the loop parts and the hook parts of the hook andloop devices.

The mat 50 is then applied to the aircraft structure 240, in this caseto respective lugs of the circumferential fuselage frames 242 (FIG. 33),then attached to the structure 240, for example by means of elasticclips 340 (FIG. 34).

FIG. 35 shows an example of such an elastic clip 340, comprising twotabs 350A, 350B connected by a head 352 and defining an expanded space354 and a narrowed portion 356. Such a clip is installed by forcing thelug 358 of a circumferential frame 242 to pass through the narrowedportion 356, making use of the elastic nature of the tabs 350A, 350B,until the lug 358 reaches the expanded space 354, where it is retainedby the tabs 350A, 350B.

Therefore, the elastic clips 340 each grip the mat 50 in combinationwith a corresponding circumferential frame lug.

The steps of detaching the mat 50 from the load-bearing structure 140and attaching the mat 50 to the aircraft structure 240 can beimplemented consecutively or concurrently.

In the first case, the whole of the mat 50 is detached from theload-bearing structure 140, then the whole of the mat 50 is attached tothe aircraft structure 240, while in the second case, certain parts ofthe mat 50 are attached to the aircraft structure while other parts ofthe mat are still attached to the load-bearing structure 140.

The method then comprises a step of removing the load-bearing structure140 from the aircraft portion 245.

The load-bearing structure can then be retracted in order to be storedwith a view to being reused to install another mat in another aircraftportion, using a similar method.

FIG. 36 shows the aircraft structure 240 equipped with the mat 50, uponcompletion of the thermoacoustic insulation method described above.

Naturally, in the variants in which the load-bearing structure 140 isnot attached to the mat in a detachable manner, the load-bearingstructure remains as an integral part of the aircraft, and the methoddoes not comprise the step of removing the load-bearing structure.

Moreover, in the variants in which the load-bearing structure is notdeployable, the insulation method does not comprise the deployment step.

While at least one exemplary embodiment of the present invention(s) isdisclosed herein, it should be understood that modifications,substitutions and alternatives may be apparent to one of ordinary skillin the art and can be made without departing from the scope of thisdisclosure. This disclosure is intended to cover any adaptations orvariations of the exemplary embodiment(s). In addition, in thisdisclosure, the terms “comprise” or “comprising” do not exclude otherelements or steps, the terms “a” or “one” do not exclude a pluralnumber, and the term “or” means either or both. Furthermore,characteristics or steps which have been described may also be used incombination with other characteristics or steps and in any order unlessthe disclosure or context suggests otherwise. This disclosure herebyincorporates by reference the complete disclosure of any patent orapplication from which it claims benefit or priority.

The invention claimed is:
 1. A method for manufacturing a thermoacousticinsulation module for an aircraft, comprising: providing a matconfigured to provide thermoacoustic insulation of an aircraft portion;followed by attaching a bendable structure to the mat; followed bybending the bendable structure, along a bending axis parallel to alongitudinal direction of the mat, such that the bendable structureforms a load-bearing structure supporting the mat in a curved shape, theload-bearing structure and the mat together forming said thermoacousticinsulation module.
 2. The method according to claim 1, wherein the stepof providing the mat comprises: providing a raw mat; followed byproducing the mat from the raw mat, comprising the production of atleast one of a plurality of porthole openings or at least one aircraftcabin door opening in the raw mat.
 3. The method according to claim 2,wherein the step of providing the raw mat comprises a step of producingthe raw mat comprising: depositing a first layer of thermoacousticinsulation on an outer film; followed by depositing a second layer ofthermoacoustic insulation on one or more first areas of the first layerof thermoacoustic insulation, leaving one or more second areas of thefirst layer of thermoacoustic insulation not covered by the second layerof thermoacoustic insulation; followed by depositing an inner film onthe second layer of thermoacoustic insulation and on the second areas ofthe first layer of thermoacoustic insulation.
 4. The method according toclaim 1, wherein the bendable structure comprises bendable battens, thestep of attaching the bendable structure to the mat comprising a step ofattaching the bendable battens to the mat such that the bendable battensare arranged in a transverse direction of the mat orthogonal to thelongitudinal direction, and spaced apart from each other in thelongitudinal direction.
 5. The method according to claim 4, wherein thestep of attaching the bendable structure to the mat comprises a step ofattaching reversible attachment devices to the mat, followed by the stepof attaching the bendable battens to the mat, using the reversibleattachment devices.
 6. The method according to claim 4, furthercomprising a step of attaching feet respectively to two opposing ends ofeach of the bendable battens, the feet being provided with at least oneof wheels or lifting actuators.
 7. The method according to claim 4,comprising, between the step of attaching the bendable battens to themat and the step of bending the bendable structure, a step of compactingthe mat that comprises: raising the segments of the mat, each situatedbetween two corresponding consecutive bendable battens, such as to givethe mat an undulated shape in the longitudinal direction; and bringingthe segments closer together, and moving the bendable battens closertogether, by compressing the segments, such as to reduce the spacerequirement of the mat in the longitudinal direction.
 8. The methodaccording to claim 7, further comprising a step of connecting thebendable battens to at least one synchronization device, connecting thebendable battens to each other in such a way as to synchronize themovements of the bendable battens relative to each other in thelongitudinal direction.
 9. The method according to claim 7, furthercomprising a step of installing a longitudinal retaining deviceconfigured to prevent the bendable battens from moving apart from eachother in the longitudinal direction.
 10. The method according to claim1, further comprising a step of installing a transverse retaining deviceconfigured to hold the load-bearing structure in its bent shape.